Butte Creek chinook salmon will get a blast of cold water this summer

From Allen Harthorn's vantage point on an elevated deck above Butte Creek, he believes there may be 10,000 spring-run chinook salmon in the creek.

A Vaki River Watcher video system lower in the creek has counted only 4,000 fish moving over a fish ladder.

(For an explanation of the system: http://goo.gl/HkppUL)

The discrepancy in fish numbers can be expected. The Vaki cameras are placed on a fish ladder. During high storm flow in March and April, fish didn't need the fish ladders to move upstream, thus they avoided the cameras, explained Clint Garman, a fish biologist with the California Department of Fish and Wildlife.

By any count, the spring-run chinook numbers look good.

Twenty-five years ago only a few hundred spring-run made the journey from ocean to Butte Creek, leading the California Department of Fish and Wildlife to name them officially threatened.

Drought brings careful water management

With drought and fish concerns, PG&E received a special variance from the Federal Energy Regulation Commission last spring to hold back as much water as possible in Philbrook Lake, and not generate power at DeSabla Powerhouse.

The Centerville Powerhouse is currently out of commission, and in the past received water through a diversion canal.

This summer if a heat spike occurs, cool water from Philbrook Lake will be strategically released higher up in Butte Creek.

Fish can die in large numbers if water is so warm that disease spreads quickly.

This happened in 2003, when 11,000 of 17,000 fish died.

The cool water releases from Philbrook was done last year with good results (see story from Aug. 2013 here: http://goo.gl/pCI9C8)

In many ways, it's intuitive to think that more cold water higher in the creek would be the best approach and that diverting water through the Centerville Canal would not benefit fish.

However, biologist Garman and PG&E spokesman Paul Moreno said sometimes having cold water lower in the creek is helpful.

Water flowing through the diversion canal moves quickly, and is shaded. If the fish spread out through the creek, the fish spread out over more spawning habitat, they said.

Yet, this year there isn't much water, and water in the canal would be slow and warm.

Last year, 90 percent of the fish moved as high up in the stream as they could, the men said.

Keeping the water higher in the creek this year will "benefit the most fish higher in the stream," this year, Moreno concluded.

Philbrook Lake holds 5,000 acre-feet of water, and in a wet year will spill and refill many times.

This year there isn't much water, and won't be much hydropower.

The best choice for PG&E is also to create hydroelectricity later in the summer when demand is at its peak, Moreno explained.

Once the spring-run chinook salmon reach the creek, they stay put until November when they spawn and die.

The snowpack, as meager as it was, is mostly gone, Moreno noted.

Hoping for the best for fish

Last year, Moreno and Garman agreed, the fish swam further up the stream rather quickly, and the cold water was available in the right place.

Harthorn, who runs the nonprofit group Friends of Butte Creek, is pleased with the management choices made.

"For the better part of June and July we'll have more water than ever" in the upper portion of Butte Creek.

More official surveys of the fish will begin June 10 and continue until November when the fish spawn.